Search for dissertations about: "mean transit time"

Showing result 1 - 5 of 12 swedish dissertations containing the words mean transit time.

2. 1. Analysis of Angiographies in Human Healthy Eyes and in Open-angle Glaucoma : Retinal Mean Transit Time and Optic Nerve Head Circulation

   Author : Gunilla Bjärnhall; Albert Alm; Göran Sperber; Selim Orgul; Uppsala universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Ophtalmology; Oftalmologi;

   Abstract : Purpose of the studies was to develop a more robust technique to determine retinal mean transit time in healthy and in glaucoma eyes and to evaluate the circulation of the optic nerve head in glaucoma patients.The retinal mean transit time impulse-response method was evaluated in human healthy eyes and normal values and reproducibility were tested. READ MORE

4. 2. Studies on Retinal Circulation in Experimental Animals, Healthy Human Eyes and Eyes with Diabetic Retinopathy

   Author : Lidija Tomić; Albert Alm; Einar Stefánsson; Uppsala universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Retinal Circulation; Labelled Microsphere Technique; Monkeys; Blue Field Simulation; Macular Leukocyte Velocity; Fluorescein Angiogram; Mean Transit Time; Impulse-Response Technique; Arterio-Venous Passage Time; Vessel Diameter; Oxygen; Carbin Dioxide; Diabetes Retinopathy; Ophtalmology; Oftalmologi;

   Abstract : The retina is a highly metabolically active tissue with large demands on the supply of nutrients. Disorders affecting the retina often include some vasculopathy with an impact on retinal circulation. READ MORE

5. 3. Optimisation and Validation of Dynamic Susceptibility Contrast MRI Perfusion Measurements

   Author : Linda Knutsson; Lund Medicinsk strålningsfysik; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Nukleärmedicin; radiobiologi; Nuclear medicine; radiobiology; radiologi; tomografi; medicinsk instrumentering; tomography; medical instrumentation; Clinical physics; cerebral blood volume; mean transit time; cerebral blood flow; perfusion; dynamic susceptibility contrast MRI arterial input function; Klinisk fysiologi; radiology;

   Abstract : The studies presented in this thesis concern the optimisation and evaluation of the dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) technique for the assessment of perfusion-related parameters of the brain, such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT). Several methodological factors influence these measurements, for example, contrast-agent administration, arterial input function (AIF) registration, choice of deconvolution algorithm and the choice of pulse-sequence parameters. READ MORE

6. 4. MRI Perfusion Measurements using Magnetic Susceptibility Effects: : Calibration Approaches and Contrast Agent Quantification

   Author : Emelie Lind; Lund Medicinsk strålningsfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; contrast agent; cerebral blood flow; cerebral blood volume; mean transit time; perfusion; dynamic susceptibility contrast MRI; magnetic susceptibility;

   Abstract : Exchange of oxygen and nutrients between blood and tissue occurs at the capillary level of the blood system. The blood volume flow rate in the capillaries is often referred to as perfusion, and knowledge about perfusion provides important information about the function and viability of the tissue, for example, in patients with ischaemic stroke, cancer, and neurodegenerative diseases. READ MORE

7. 5. Applications of Magnetic Tracers in the Human Lung and Gastrointestinal Tract

   Author : Mikael Forsman; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; inverse solution; gastrointestinal motility; inhaled particles; gastric emptying; welding dust; MPG; pulmonary clearance; occupational health; magnetopneumography; multipole analysis; transit time;

   Abstract : The use of ferrimagnetic material as a tracer represents a noninvasive approach in physiological measurements. Concerning the lung, magnetopneumography, MPG, is a unique technique to estimate retained dust in the lung, using the magnetizable dust fraction as a tracer. First a strong constant magnetic field is briefly applied to the thorax. READ MORE